Catalytic Cracking of Oily Sludge using Nickel Metal Catalyst Embedded in Silica Derived from Adsorbent in a Gas Process Plant

One of the oily sludges (OS) recycling methods is through catalytic cracking. This process involves the reaction of breaking down large molecules into smaller ones with the help of a catalyst. Nickel (Ni) metal is often used as a catalyst because it can increase fuel liquid yield while reducing the coke formation. To enhance its performance, Ni metal can be embedded in a carrier material like Silica to form the Ni-Silica catalyst. In this research, OS sourced from a gas process plant is treated with catalytic cracking using Ni-Silica, where the silica used is derived from an adsorbent activated with NaOH. The cracking conditions are optimized using Response Surface Methodology (RSM) with a Box-Behnken design. The optimized cracking reaction conditions include temperature (713 K, 723 K, and 733 K), time (50 min, 60 min, and 70 min), and catalyst to OS ratio of 1:5, 1:6, and 1:7. Statistical analysis indicates that the relationship between the reaction condition variables and the oil liquid product (OLP) falls into the moderate category, as shown by the coefficient of determination (R²) of 0.5. The calculated F-value for the deviation from the mathematical model is smaller than the F-Table value (9.2) at both 5 and 1 significance levels, with a value of 0.6. This indicates that the mathematical model generated can be accepted as the mathematical model within the range of reaction conditions in this study. Calculus analysis reveals that the optimum reaction conditions are a temperature of 717.34 K, a time of 58.58 min, and a catalyst to OS ratio of 1:6. Canonical analysis indicates that for OLP, λ1= -12.38, λ2= -2.27, and λ3= 4.50, where lambda values indicate that the most sensitive response surface parameter for OLP is temperature, followed by the catalyst to sample ratio, and the least sensitive is reaction time. © 2024, Gadjah Mada University. All rights reserved.